A targeting device for an intramedullary cavity nail substantially as defined above is already known from e.g. EP 1 455 662 B1.
The construction and function of this prior art targeting device is substantially satisfactory. However, it provides no means for assisting in eliminating the problems arising when e.g. the bone fragment or bone fragments located distally of an unstable trochanteric femur fracture, primarily the femoral shaft of the femur, and the bone fragment or bone fragments located proximally of the unstable trochanteric fracture, primarily the femoral head of the femur, during secondary compression, i.e compression after surgery, strives to be displaced, relatively seen, towards each other along the longitudinal axes of the femoral shaft and the cavity nail the-rein. During such secondary, dynamic biaxial compression of unstable trochanteric femur fractures, the compression is counteracted by the femur neck screw, because said femur neck screw, screwed into the bone fragments on both sides of the unstable trochanteric fracture, does not allow such compression.